From day one, critics panned Apple's voice-powered assistant Siri for being more gimmicky than useful.

It's pretty good for controlling your phone –– placing a call by saying "call Mom" or setting your alarm by telling it what time you want to wake up. But when it comes to searching the Web for the answers you want, Siri is a dud.

That became all the more apparent last year when Google introduced Google Now, its own voice-powered assistant for Android devices. Google Now can do everything Siri does, but has the advantage of tapping into Google's massive trove of data to bring you the answers you're looking for. In that regard, Google Now is far more intelligent and accurate than Siri.

The brilliant part about Google Now is that it just knows you based on what you do in other Google services like search, calendar, and Gmail.

For example, if you have a meeting scheduled in your calendar, Google Now will tell you when to leave and how to get there so you make it on time. It even takes traffic into account. If Amazon sends you an email saying your package has shipped, Google Now will display the tracking information. It automatically pulls in scores for your favorite sports teams based on your search history.

And that's just scratching the surface.

Google Now is an assistant that shows you what you need before you even have to ask it to. Siri makes you tell it what you want, and it doesn't always get it right after you do.

When it comes to search, Google has the advantage. It's been collecting the world's information for nearly 15 years, and it can use all that to intelligently display the correct answer to your question, or answer it the way you want. Need a video of Psy's latest single? Just ask Google Now to show it to you.

Siri relies largely on Wolfram Alpha, a so-called "knowledge engine," to give you answers and refers you to a regular Google search for everything else. It adds an extra layer of pain to your queries.

Today's launch is also a fascinating example of how Google is squirming its way onto iOS with apps and services that are better than the ones Apple ships with the iPhone. In the last year Google has given us: Google Maps (better than Apple Maps), YouTube (much better than the old Apple-made YouTube app), Capture (a great way to quickly upload videos to YouTube), and a new version of Gmail that syncs better with the email service.

There are a few caveats.

Google Now for iOS doesn't have push notifications, so you won't get an alert when new information comes through. It's a bit odd that Google left that feature out, but hopefully they're coming soon. (On the other hand, Siri doesn't send you notifications either.) Google Now also can't control basic functions on your phone, so you won't be able to tell it to send a text, set a reminder, make a new calendar appointment, etc.

And Siri is getting a little better. In its latest update, Siri can tell you stuff like sports scores and stats along with movie times and reviews.

But all that isn't nearly as robust as what Google Now gives you. It's an extension of you, a clever assistant that pulls in your online identity and helps you make the most out of it. Siri has a long, long way to go before it can achieve that.